"With so few concurrent civilizations, and such large distances, it is little surprise that the SETI project has not found that alien signal. Our nearest neighb

"With so few concurrent civilizations, and such large distances, it is little surprise that the SETI project has not found that alien signal. Our nearest neighbor is 4 light years away, and there are under 100 stars within 50 light years, the total of the project's existence." That doesn't change Enrico Fermi's calculations on how long it might take an alien civilization to colonize the galaxy (max 100 million years). Or spam every solar system with Von Neumann probes. Or build giant radio emitters and send them out to various parts of the galaxy to ensure coverage. As long as there's a decent chance other alien civilizations have emerged before our own in the Milky Way, there is a paradox until we know why they aren't detectable. Or seeing Type 3 civilizations in other galaxies.